Method for processing metal working fluid

ABSTRACT

A method for processing metalworking fluid disposed in a sump 12 is disclosed and includes the step of collecting metalworking fluid having a greater concentration of tramp oil than the concentration in the sump and flowing a portion of this oil, without passing the oil through a separator, to increase circulation in the sump. Various steps of the method are developed which increase the level of tramp oil removed from the sump and provide for the introduction of oxygen into the working medium of fluid. In one particular embodiment of the method, the step of flowing the return fluid under pressure to the sump, includes forming jets of fluid which extend vertically into the air to aerate the metalworking fluid and block the proliferation of anaerobic bacteria.

CROSS-REFERENCE TO RELATED APPLICATION

This application relates to copending U.S. application Ser. No.08/997,938 entitled "Apparatus for Receiving Metalworking Fluid", byDavid R. Fortier, and copending U.S. application Ser. No. 8/997,939entitled "Apparatus for Processing Metalworking Fluid", by David R.Fortier.

TECHNICAL FIELD

This invention relates to an apparatus for processing metalworkingfluids used with tools for removing metal, and, more particularly for amethod of processing the fluid to remove contaminants and retard thegrowth of bacteria.

BACKGROUND

Metalworking processes use machines having cutting tools, grindingdevices or other tools to remove metal from a workpiece. These toolsgenerate heat by sliding friction at the interface between the tool andthe workpiece. Metalworking fluids are sprayed on the interface to washaway chips, improve surface finish, increase tool life, reduce the powerrequired and to cool the tool and the workpiece. These fluids arecommonly called coolant because cooling is one of the major functions ofthe fluids.

There are a wide variety of metalworking fluids including compoundedmineral oils, fixed and sulfurized oils, and water and oil emulsions.Emulsions of water and water soluble oil are one class of metalworkingfluids widely used for metalworking processes. The emulsion resemblesmilk in appearance, is not expensive and has low viscosity permittingthe emulsion to separate readily from the chips. In addition, theemulsion has good coolant properties for removing heat from the tool andwork piece to keep their temperatures within acceptable limits.Unacceptable levels of temperature in the cutting tool or the work piececan result in deterioration of both the work piece and the cutting toolultimately resulting in failure of the cutting tools or irreparabledamage to the work piece.

In one application, an emulsion of 95% water and 5% lubricating oil issprayed on the tool and on the workpiece. As the metalworking fluid issprayed on the workpiece and cutting tool, the metalworking fluidperforms its functions, such as cooling, and drains to a fluid sump. Thesump is disposed beneath the machine and collects the metalworkingfluid, along with chips and other debris carried by the fluid. The fluidalso carries tramp oil which has leaked from gear boxes andtransmissions on the machine, or which has lubricated sliding surfaceson the ways, and which was protecting the workpiece from corrosion priorto a machining operation. The tramp oil floats on the surface of thefluid in the sump.

The metalworking fluid contaminated with tramp oil is creates an idealbreeding place for anaerobic bacteria in the sump. The tramp oil forms alayer on the top of the fluid, sealing the fluid from contact withoxygen in the air. The bacteria breed, consuming the tramp oil fornourishment and ultimately degrading the quality of the fluid to such anextent that it no longer performs it useful function and turns rancid.The fluid is then discarded.

One approach to removing the tramp oil is to dispose a conduit having afloating inlet within the upper layer of fluid in the sump. The floatinginlet is in flow communication with a separator for separating tramp oilfrom the fluid. The separator typically has a tortuous flowpath alongwhich the fluid is flowed. The flow path leaves the tramp oil in aseries of pools at the top of the separator, separating the tramp oilfrom the fluid. The tramp oil is removed and the now, less contaminatedfluid returns to the sump. Occasionally, the floating inlet for theseparator conduit sinks below the surface of the fluid in the sump andprimarily returns pure fluid to the separator leaving the tramp oil onthe top layer of the fluid with the unfortunate results described above.

Accordingly, personnel working under the direction of Applicant'sassignee have sought to develop a fluid processing system which wouldseparate tramp oil from the fluid and retard the growth of anaerobicbacteria within the fluid.

SUMMARY OF INVENTION

This invention is in part predicated on the recognition that flow to theseparator is such a low level that circulation of the metalworking fluidwithin the metalworking fluid sump results in dead zones of little or nocirculation in the sump in which bacteria and other harmful microorganisms flourish once a thin film of tramp oil forms on the fluid inthe dead zone.

According to the present invention, a method for processing metalworkingfluid having tramp oil disposed in the sump includes circulating anadditional amount of the metalworking fluid from the sump and returningit to the sump at a flow rate which is greater than the flow rate whichis passed through the separator such that positive circulation ofmetalworking fluid takes place in predetermined dead zones of themetalworking fluid sump.

In accordance with the present invention, the step of circulating anadditional amount of metalworking fluid from the sump includes aeratinga portion of the metalworking fluid which is bypassed from theseparator.

In accordance with one detailed embodiment of the present invention, themethod of aerating the metalworking fluid includes forming a vortex asthe fluid is sucked from a collection chamber to entrain air into themetalworking fluid and retard the growth of anaerobic bacteria. Inaccordance with another embodiment of the present invention, a portionof the returned metalworking fluid is aerated by spraying jets ofmetalworking fluid which extend vertically, breaking the plane of thesurface of the metalworking fluid and impacting the underside of themachine and returning to the sump enriched with oxygen.

A primary feature of the present method is the step of recirculating aportion of metalworking fluid to the sump at a rate which is equal to orgreater than the flow rate of metalworking fluid going to the separatorto positively distribute metalworking fluid within selected dead zonesin the sump. This may include flowing a portion of the fluid from theseparator under pressure to the sump. Another feature of the presentinvention is the step of aerating the metalworking fluid as the fluid issucked from the sump. A feature of one embodiment of the presentinvention is the step of aerating the metalworking fluid as metalworkingfluid is returned to the metalworking fluid sump by spraying themetalworking fluid against a portion of the machinery above themetalworking fluid sump.

A primary advantage of the present invention is the decreased cost ofoperating a metalworking fluid system for a machine tool which resultsfrom retarding the formation of bacteria within the metalworking fluidand separating the tramp oil from the metalworking fluid. Anotheradvantage of the present invention is the health and safety of the workplace which results from avoiding the formation of bacteria in themetalworking fluid and odors associated with such metalworking fluid.Still another advantage of the present invention is the level oflubricating properties and cooling properties of the metalworking fluidduring the life cycle of the metalworking fluid which results fromreducing the level of contaminants in the metalworking fluid.

The foregoing features and advantages of the present invention willbecome more apparent in light of the following detailed description ofthe best mode for carrying out the invention and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a machine for metalworking having a sumpdisposed beneath the machine for receiving metalworking fluid.

FIG. 2 is a perspective view of the machine shown in FIG. 1 with themachine shown in phantom, and shows the sump and fluid distributionsystem for the sump which is disposed in the sump.

FIG. 3 is a schematic representation of an apparatus for processingmetalworking fluid which includes the sump and the embodiment of thefluid distribution system shown in FIG. 2.

FIG. 4 is a side elevation view of a collection chamber partially brokenaway to show a conduit and an orifice disposed in the collectionchamber.

FIG. 4A is a top view of the collection chamber with lines of flow ofthe metalworking fluid shown by arrows.

FIG. 5 is a side elevation view of an alternate embodiment of thecollection chamber shown in FIG. 4.

FIG. 5A is a top view of the embodiment of the collection chamber shownin FIG. 5.

FIG. 6 is an alternate embodiment of the apparatus for processingmetalworking fluid shown in FIG. 3.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a perspective schematic, view of a machine 10 formetalworking. The machine has a sump 12 disposed beneath the machine forreceiving metalworking fluid. The machine has a spray system (not shown)for spraying metalworking fluid on a workpiece (not shown). Asubstantial portion of the metalworking fluid for the spray system isdisposed in the sump 12 beneath the machine where it is recirculated bythe spray system.

FIG. 2 is a perspective view of the machine 10 shown in FIG. 1 with themachine shown in phantom. FIG. 2 shows the sump 12. A fluid distributionsystem 14 for the sump is disposed in the sump beneath the machine. Thefluid distribution system is disposed below the surface level S of thefluid. The sump has regions of fluid circulation under operativeconditions which include at least one region R of potentially lowercirculation. The regions of potentially lower circulation result fromthe contour of the sump and portions of the machine which extend intothe sump. These create zones of little or no circulation unless thefluid is positively circulated by the fluid distribution system.

FIG. 3 is a schematic representation of an apparatus 18 for processingmetalworking fluid which includes the sump 12 and the embodiment of thefluid distribution system 14 shown in FIG. 2. As shown in FIG. 3, theapparatus for processing metalworking fluid includes a separator 22 forprocessing metalworking fluid that has tramp oil. The separator issimply represented as a tank 24 having an inlet chamber 26 and an outletchamber 28. A continuous flow path 32 for the metalworking fluid extendsthrough the tank. Downwardly projecting baffles 34 and upwardlyprojecting baffles 36 define the flow path. The baffles divide the tankinto a plurality of separation regions 38 each having a pool 39 at thetop of the separation region. The pool has a collection chamber 40disposed in the separator. One acceptable separator is the Tramp Champmodel separator, available from Porter Systems, Inc., P.O. Box 535,Bridgeport, N.Y. 13030.

The apparatus 18 for processing metalworking fluid includes acirculation system 42. The circulation system is in flow communicationwith the separator 22 and the fluid distribution system 14 for the sump12. The circulation system removes metalworking fluid from the sump,flowing an amount of fluid per unit time from the sump. A first amountper unit time is sent to the separator. A second amount per unit timeby-passes the separator 22 and is sent directly to the fluiddistribution system 14 in the sump.

The circulation system 42 uses one or more pumps 44 for flowing themetalworking fluid through the system. In the embodiment shown, a singlepump is used with appropriate valuing V1, V2, V3. Pumps in fluidcommunication with two or more of the conduits or disposed in the fluiddistribution system in the sump 12 are equivalents of the one or morepumps shown in FIGS. 3 and 5.

The circulation system 42 includes an apparatus 46 for receiving(collecting) metalworking fluid. The apparatus includes a collectionchamber 48 and at least one collection orifice 52 or more as shown inFIGS. 4-5A. The orifice is at the collection chamber and may be separatefrom the collection chamber or formed integrally with the collectionchamber, such as by simply boring a hole in the chamber.

The collection chamber 48 is disposed in the pool of metalworking fluidin the sump 12. The collection chamber has an interior 54 having acollection region 55. The interior adapts the chamber to receivemetalworking fluid having a higher concentration of tramp oil than theadjacent fluid in the sump 12 (that is, the concentration of tramp oilper unit volume of metalworking fluid in the collection chamber isgreater than the concentration of tramp oil per unit volume of fluid inthe sump less the amount of working fluid in the collection chamber).

The interior 54 of the chamber is bounded by a wall 56. The wall has atleast one opening 58 at a level which is approximately equal to thelevel of fluid (height H of fluid) such that an upper portion of fluidin the sump flows into the collection chamber 48 through the opening 58.

One or more first collection conduits 62 are in flow communication withone or more collection chambers 48. All conduits, such as conduit 62,have an associated flowpath designated by the addition of the letter f(62f). Each collection conduit has at least one leg 64 in flowcommunication through the collection orifice 52 and with the interior 54of the collection chamber. The collection conduit has an adjustablevalve V1. The pump 44a has a first inlet 66 in flow communication with acollection conduit 62a for another sump (not shown). A second inlet 68is in flow communication through the first collection conduit with thesump 12. The pump has one or more outlets such as the first outlet (notshown) for pressurized flow to the sump 12, a second outlet 72 forpressurized flow from the other sump to the separator 22 and a thirdoutlet 74 for pressurized flow to the separator. A second separatorconduit 76 places the outlet 74 of the pump in flow communication withthe inlet 26 to the separator 22. A third return conduit 78 extends fromthe separator for returning metalworking fluid to the sump 12 with asmaller concentration of tramp oil than the concentration of tramp oilin the fluid of the sump . A fourth return conduit 82 is in flowcommunication with the collection conduit through the outlet of thepump. The fourth return conduit supplies pressurized flow to the fluiddistribution system 14 through the valve.

The fluid distribution system 14 in the sump 12 has a first conduit 84and a second conduit 86 in flow communication with the fourth returnconduit 82. The fluid distribution system supplies pressurized fluid tothe sump 12. The first conduit has a first leg 88 having a flow path 88fwhich extends into a region of naturally lower circulation of the sump.The first leg of the conduit has a plurality of exit orifices, asrepresented by the arrows 92 (angled at an angle of twenty (20) degreesto the direction of the flowpath in a horizontal plane and at an angleof twenty to twenty-five (20-25) degrees upwardly in a vertical plane).The exit orifices direct fluid away from the conduit and upwardly towardthe surface S of the fluid in the fluid sump 12. A second leg 94 has aflowpath 94f and has a plurality of exit orifices 96 which extend in avertical direction for directing jets of fluid through the fluid, intothe air above and against the underside of the machine which is shown inFIG. 1 and FIG. 2.

The second conduit 86 has a first leg 98 having a flow path 98f whichextends into a region R of naturally lower circulation of the sump. Theconduit has a plurality of exit orifices, as represented by the arrows102 (angled at an angle of twenty (20) degrees to the direction of theflowpath in a horizontal plane and at an angle of twenty to twenty-five(20-25) degrees upwardly in a vertical plane). The exit orifices 102direct fluid away from the conduit 86 and upwardly toward the surface Sof the fluid in the fluid sump 12. A second leg 104 has a flowpath 104fand has a plurality of exit orifices 106 which extend in a verticaldirection for directing jets of fluid through the fluid, into the airabove and against the underside of the machine 10 which is shown in FIG.1 and FIG. 2.

Lines of flow F are shown in the sump 12. These lines of flow representone flow pattern for the metalworking fluid in the sump. The lines offlow extend through regions R of potentially low or no flow urgingmetalworking fluid to circulate in the sump. As a result, metalworkingfluid containing tramp oil is in flow communication with the remainingfluid in the sump. This insures that the tramp oil on the surface hashad an opportunity to move into a region adjacent the collectionchambers 48. As will be realized, the same orientation of fluid conduits84,86 for the same sump 12 may result in different flow patterns fordifferent machines. This results in part from contours of the differentmachines which distribute sprayed metalworking fluid to regions of thesump that differ from regions shown in FIG. 1 and from support structureof the different machines which might extend at other locations into thesump.

FIG. 4 is a side elevation view of a collection chamber 48 partiallybroken away to show the collection conduit 62 and a collection orifice52 disposed on the interior 54 of the chamber. In the embodiment shown,the wall 56 of the collection chamber is a curved surface and, inparticular, is cylindrical. In other embodiments, the wall might be oneof four walls forming a rectangle, a square or other shapes.

The cylindrical wall 56 extends circumferentially about the interior 54of the chamber 48. The cylindrical wall is disposed about an axis ofsymmetry A. A bottom 108 extends from the wall and seals the bottom ofthe collection chamber. In alternate embodiments, the bottom of thecollection chamber might be open with the bottom of the collectionchamber sealed by the bottom of the sump.

A plurality of cylindrical openings 58 extend through the wall 56. Theopenings 58 are circumferentially spaced one from the other. Theopenings 58 have a diameter which is approximately equal to one-thirdthe height of the collection chamber 48. Each cylindrical opening has acenter located at a position which is approximately level with the levelof coolant H in the sump 12 under normal operative conditions. In theembodiment shown, the collection chamber is approximately four andone-half inches high, has a cylindrical opening 58 having a diameter ofapproximately one and one-half inches and the center of the opening 58is approximately three inches from the bottom 108 of the chamber.

The collection chamber 48 includes a plurality of collection orifices 52that are in flow communication with the leg of the first collectionconduit 62. The collection orifices face in a predetermined directionfor sucking fluid from the collection chamber. The orifices are disposedat a level which is below the level of the opening in the wall. In theembodiment shown, the collection orifice to spaced less than one-half ofan inch (approximately three tenths of an inch) from the bottom surfaceof the opening. As shown the orifices face in a vertical direction awayfrom the bottom of the collection chamber.

FIG. 4A is a top view of the collection chamber 48. Lines of flow of themetalworking fluid are shown by arrows in the collection chamber. Asshown in FIG. 4A, the collection chamber has three orifices 52, two ofwhich are spaced ninety degrees from the third. Lines of flow in thechamber are represented by the arrows Fv showing formation of the vortexat each orifice. Lines Fc show general circulation within the collectionchamber that results in part from the flow Fv at the orifices.

FIG. 5 is a side elevation view of an alternate embodiment 48a of thecollection chamber 48 shown in FIG. 4. The collection chamber 48a has abottom 112 and a top 114. The first conduit 62a has a leg 64a extendingdown through the top of the collection chamber. In this embodiment, thecollection chamber has two orifices 52a spaced a distance below theopening 58 which is more than one inch. The orifices face in thehorizontal direction, that is, perpendicular to the wall 56. Experiencehas shown that a significantly greater flow rate is required toestablish a vortex than for the FIG. 4 embodiment.

FIG. 5A is a top view of the embodiment of the collection chamber 48ashown in FIG. 5 showing the vortex Fv and the lines of flow Fd.

FIG. 6 is an alternate embodiment 18a of the apparatus 18 for processingmetalworking fluid shown in FIG. 3. In FIG. 6, the circulation system 42includes an intermediate supply tank 116. A pump 118 suppliespressurized fluid to the fluid distribution system 14. The third conduit78a from the separator 22 having unpressurized clean fluid and thefourth conduit 82a having pressurized collected fluid are fed into theintermediate tank. The metalworking fluid in the tank has a tramp oilconcentration which is greater than the tramp oil concentration in thecollected fluid from the separator 22, but less than the tramp oilconcentration in collected fluid from the fourth conduit.

During operation of the apparatus 18 shown in FIG. 3, the apparatusprocesses the metalworking fluid. The collection region 55 is formed onthe interior 54 of the collection chamber 48 which has metalworkingfluid having a higher concentration of tramp oil than the concentrationof tramp oil in the sump 12. The orifices 52 of the collection chamberare disposed close to the surface of the fluid. Less metalworking fluidenters with the tramp oil. As a result, the tramp oil concentration ofthe fluid sucked in by the orifice 52,52a is even greater than theconcentration of tramp oil generally in the collection region, makingthe tramp oil concentration flowed to the separator 22 even greater thanthe concentration of tramp oil in the sump. Having provided the sumpwith a fluid distribution system 14 to circulate flow in the sump, theamount of collected fluid is divided in the circulation system 42between the separator and the fluid distribution system. The fluidreturned from the circulation system to the sump 12 through the fluiddistribution system provides pressurized fluid which is directed atregions of lower circulation.

In the embodiment shown, the fluid returned to the sump 12 may also beaerated by spraying the fluid into the air and against the machine 10 tofurther expose the fluid to air. The air contains oxygen and provides anunfriendly environment to anaerobic bacteria. In addition, the spraybreaks the surface S of the fluid, carrying oxygen back down through thetramp oil and into the metalworking fluid in the sump.

In the embodiment shown in FIG. 6, the metalworking fluid is flowed toan intermediate tank 116 which contains a reservoir of working mediumfluid. This reservoir of fluid is used to add fluid to the sump 12 bymeans of the pump 118. The flow rate of the pump is responsive to thelevel of coolant in the sump by conventional electrical, flow and/orpressure sensing means (not shown). This allows for the intermediatetank to supply fluid to the sump 12 should evaporation or heavy cuttingrequire the usage of increased levels of metalworking fluid which wouldlower the level of metalworking fluid in the sump 12 so that the levelfalls below the openings 58 to the collection chamber 48. This insuresthat the pump is constantly supplied with fluid and fluid continuouslyflows through the pump.

In either of the FIG. 3 or FIG. 6 embodiments, a particular advantage ofthe present invention is the ability to flow the required amount ofpressurized circulation fluid to the sump 12 and to tailor the flow toinsure that regions of low or no flow are avoided and to retard thegrowth of anaerobic bacteria which may spoil the metalworking fluid ordegrade its performance. As shown by the lines of circulation in FIG. 3,oil moves towards the collection chamber and the conduits, typicallymade of polyvinyl chloride (PVC) tubing, may be easily altered orflexibly oriented for installation or as required to provide fornecessary circulation.

The separator 22 has limited flow capacity and benefits from the twiceincreased concentration of tramp oil in the fluid flowed to theseparator. This increase in concentration of tramp oil results fromoperation of the collection chamber 48.

Another benefit of the collection chamber is the formation of vorticesin the collection chamber 48. These vortices combine to reinforce eachother in the collection chamber shown in FIG. 4 and causecircumferential circulation of the metalworking fluid in the chamber.The lighter tramp oil is forced inwardly by the more dense metalworkingfluid moving outwardly in response to this rotational movement of thefluid, This forces the lighter tramp oil to concentrate about the axisof the collection chamber where it is sucked into the orifice forprocessing at the separator 22. Another benefit is the ability to adjustthe size of the vortex by regulating flow. This controls the amount ofair the vortex entrains into the metalworking fluid. The valves and thusthe flow are adjusted to insure that the vortex does not ingest too muchair. Too much air would cause cavitation in the pump. Nevertheless, thevortex is big enough to provide the circulation described above forincreasing the tramp oil density in the collected flow.

Although the invention has been shown and described with respect todetailed embodiments thereof, it should be understood by those skilledin the art that various changes in form and detail thereof may be madewithout departing from the spirit and the scope of the claimedinvention.

What is claimed is:
 1. A method for processing metalworking fluiddisposed in a sump which has a pool of the fluid having a surface, thesump having regions of fluid circulation which includes at least oneregion of potentially lower circulation under operative conditions, andhaving tramp oil which accumulates at the surface of the pool at a firstconcentration per unit of fluid and which is removed by flowing aportion of the fluid to a separator, comprising:collecting fluid fromthe sump from a collection region, the collected fluid having a second,greater concentration of tramp oil than the first concentration in thesump; providing a fluid distribution system to the sump which has a flowpath in fluid communication with the region of lower circulation;flowing an amount of collected fluid from the sump which includesflowing a first amount of the collected fluid per unit of time to aseparator for decreasing the concentration of tramp oil in the collectedfluid to a third concentration; flowing the first amount of collectedfluid per unit of time having the third concentration of tramp oil tothe sump; flowing a second amount of collected fluid per unit of time tothe fluid distribution system which has a concentration of tramp oilthat is greater than the decreased third concentration of the firstamount;wherein the second amount of collected fluid flowed to the fluiddistribution system for the sump is at least equal to the first amountof collected fluid flowed to the separator per unit of time, wherein thesecond amount is directed with at least one jet toward a location whichurges metalworking fluid in the sump to circulate toward the collectionregion and wherein the increased concentration of tramp oil flowed tothe separator as compared to the concentration in the sump increases theamount of tramp oil removed by the separator per unit of flow of sumpfluid.
 2. The method for processing metalworking fluid disposed in asump having a pool of such fluid of claim 1 wherein the step ofcollecting fluid from a collection region includesdisposing a collectionchamber in the sump which bounds the collection region, the chamberbeing in flow communication with the uppermost one inch depth of fluidadjacent the chamber; and flowing the fluid into the collection chamberfrom the upper most one inch depth of fluid adjacent the collectionchamber.
 3. The method for processing metalworking fluid disposed in asump having a pool of such fluid of claim 2 wherein the second amount ofcollected fluid flowed to the sump through the fluid distribution systemis greater than the first amount and includes at least a portion of thefirst amount of collected fluid.
 4. The method for processingmetalworking fluid disposed in a sump having a pool of such fluid ofclaim 2 wherein the step of flowing an amount of collected fluid fromthe sump includes sucking an amount of collected fluid per unit of timefrom the collection chamber at a flow rate which causes the level of thefluid in the collection chamber to be lower than the level of fluid inthe sump.
 5. The method for processing metalworking fluid disposed in asump having a pool of such fluid of claim 2 wherein the step of flowingan amount of collected fluid from the sump includes forming a vortex inthe collected fluid within the collection chamber.
 6. The method forprocessing metalworking fluid disposed in a sump having a pool of suchfluid of claim 1 wherein the step of flowing an amount of collectedfluid from the sump includes forming a vortex in the collected fluid. 7.The method for processing metalworking fluid disposed in a sump having apool of such fluid of claim 1 wherein the fluid distribution system hasa first flowpath and a second flowpath; and wherein the step of flowinga second amount of collected fluid per unit of time to the fluiddistribution system includes flowing a first part of the collected fluidalong the first flowpath and forming a plurality of jets of fluid whichare angled toward an area of potentially lower fluid circulation in thesump.
 8. The method for processing metalworking fluid disposed in a sumphaving a pool of such fluid of claim 7 which includes the step offlowing a first part of collected fluid along the first flowpath andforming a plurality of jets of fluid which includes angling the jets ata horizontal angle to the flowpath and angling the jets upwardly todirect the jets toward tramp oil at the surface and toward an area ofdecreased fluid circulation in the sump.
 9. The method for processingmetalworking fluid disposed in a sump having a pool of such fluid ofclaim 7 which includes flowing a first part along the first flowpathfurther includes flowing a second part of collected fluid along thesecond flowpath and forming a plurality of jets of the collected fluidwhich are oriented in a vertical direction and break through the surfaceof the fluid entering the ambient air above the sump.
 10. The method forprocessing metalworking fluid disposed in a sump having a pool of suchfluid of claim 9 wherein the step of forming a plurality of jets of thecollected fluid which are oriented in a vertical direction and breakthrough the surface of the fluid entering the ambient air above thesump, includes the steps of impacting the jet on the underside of ametalworking machine while aerating the collected fluid.
 11. A methodfor processing metalworking fluid disposed in a sump having a pool ofsuch fluid, the sump having at least a portion extending beneath amachine, having regions of fluid circulation at least one of which ispotentially a region of lower circulation under operative conditions,the fluid being contaminated with tramp oil which accumulates at thesurface and which is removed by flowing a portion of the fluid to aseparator, comprising:disposing a collection chamber in the sump in flowcommunication with the uppermost one inch depth of fluid which isadjacent the chamber; collecting fluid in the collection chamber byflowing an amount of fluid per unit of time from the upper most one inchdepth of fluid adjacent the collection chamber into the collectionchamber, the collected fluid in the collection chamber having a greaterconcentration of tramp oil per unit of volume of fluid in the chamberthan tramp oil in the sump; sucking an amount of collected fluid perunit of time from the collection chamber at a flow rate which causes thelevel of the fluid in the collection chamber to be lower than the levelof fluid in the sump, the step of sucking the collected fluid includingforming a vortex in the collected fluid, and aerating the collectedfluid; flowing a first amount of the collected fluid per unit of time toa separator to decrease the concentration of tramp oil in the collectedfluid; flowing the first amount of collected fluid per unit of timehaving a decreased concentration of tramp oil to the sump; flowing asecond amount of collected fluid per unit of time which has a secondconcentration of tramp oil that is greater than the decreasedconcentration of the first amount, to a fluid distribution system havinga first and a second flowpath disposed within the sump whichincludesflowing a first part along the first flowpath and forming aplurality of jets of fluid which are angled at a horizontal angle to theflowpath and angled upwardly to direct the jets toward tramp oil at thesurface and toward an area of decreased fluid circulation in the sump;flowing a second part along the second flowpath and forming a pluralityof jets of the collected fluid which are oriented in a verticaldirection and break through the surface of the fluid entering theambient air above the sump, which includes the steps of impacting thejet on the underside of the machine and aerating the collectedfluid;wherein the second amount of collected fluid flowed to the fluiddistribution system in the sump is at least equal to the first amount ofcollected fluid flowed to the separator per unit of time, wherein oxygenadded to the collected fluid in the collection chamber and in thevertical jets from the sump blocks the growth of anaerobic bacteria inthe metalworking fluid, wherein the jets of collected fluid in the sumpforce the circulation of fluid in the sump toward the collection chamberand wherein the increased concentration of tramp oil flowed to theseparator as compared to the concentration in the sump increases theamount of tramp oil removed by the separator per unit of flow of sumpfluid.
 12. The method for processing metalworking fluid disposed in asump having a pool of such fluid of claim 11 wherein the second amountof collected fluid flowed to the fluid distribution system in the sumpis at least twice the first amount of collected fluid flowed to theseparator per unit of time.
 13. The method for processing metalworkingfluid disposed in a sump having a pool of such fluid of claim 11 whereinthe amount of collected fluid per unit of time is such that a volume offluid equal to the volume of fluid in the sump is collected less thanone hour.